A filter is an important part of an aquarium and has the effect of filtering impurities in water, fish excrement, fish secretions, residual feeds, rotten branches and leaves of aquatic plants and other wastes in the water by using a filter element in the filter, so that various indexes of the water are regulated, the water in the aquarium is kept fresh and transparent, and the quality of the water in the aquarium is kept stable. A filter system may include three filtration ways including physical filtration, chemical filtration and biological filtration according to a working principle.
Physical filtration is a method for obstructing insoluble impurities and wastes in water by using the filter element 2. After the filter operates for a period of time, as shown in FIG. 1, insoluble impurities 01 may be accumulated at the side, close to a water inlet 3 of the filter, of the filter element 2, and therefore, the filter element 2 is required to be washed regularly to ensure the normal operation of the filter.
At present, two methods for washing the filter element 2 are mainly provided, one of the methods is to take out the filter element 2 to be washed after dismounting a filter cartridge 1, and the other method is shown as FIG. 2, a backwashing method is adopted, namely clear water enters from a water outlet 4 and washes the insoluble impurities 01 out of a drain outlet 5. The former of the two washing methods is cumbersome in process and low in efficiency due to a requirement for dismounting the filter cartridge 1, the latter of the two washing methods may result in bloated appearances of the filter and even the whole aquarium due to a requirement for redundant external pipelines, in addition, the switching operation of a plurality of valves is troublesome and error-prone.